1. Field of Invention
The invention relates to a light emitting unit and a back plate thereof that have strengthened structural intensity.
2. Related Art
By the digital era, the technology of liquid crystal displays (LCD) has been developed rapidly and the LCDs have become one of the indispensable electronic products. Accordingly, the requirements for the technique and functions of the LCD become more critical.
In general, the LCD mainly includes a LCD panel and a backlight module. The LCD panel includes two substrates and a liquid crystal layer sandwiched between the substrates. The backlight module emits light, which uniformly illustrates the surface of the LCD panel, so the backlight module can be a light emitting unit. Of course, the light emitting unit is widely used in many application fields, other than the backlight module, such as the light source of varies electronic apparatuses and the illustration of daily life.
As shown in FIG. 1, a conventional light emitting unit 1, which is for example a direct type backlight module, includes a back plate 11, a plurality of fluorescent lamps 12, a diffuser 13, a frame housing 14, a plurality of lamp fixing base 15 and a plurality of spacers 16. The spacers 16 are disposed at two ends of each fluorescent lamp 12. The fluorescent lamp 12 passes through a through hole 151 of the lamp fixing base 15 and is fixed therein, so that the fluorescent lamps 12 can be disposed on the back plate 11. Herein, the fluorescent lamps 12 are, for example, linear fluorescent lamps. The back plate 11 has a plurality of first fixing portions 111 and a plurality of second fixing portions 112. The first fixing portions 111 are disposed at two opposite edges of the back plate 11, and the second fixing portions 112 are disposed at the other two opposite edges of the back plate 11. The diffuser 13 is disposed over the fluorescent lamps 12 for uniforming the light emitted from the fluorescent lamps 12. For example, the diffuser 13 can be disposed on the lamp fixing base 15. Of course, the light emitting unit 1 may further include other optical films such as a prism film, a top diffusion film, and a bottom diffusion film (not shown). The frame housing 14 is disposed on the diffuser 13 and is connected with the first fixing portions 111 and the second fixing portions 112 by screwing or wedging. By this way, the diffuser 13 can be fixed between the frame housing 14 and the lamp fixing base 15.
The back plate 11 is usually made of metal. Different sizes of molds must be firstly prepared for manufacturing the light emitting unit of different sizes. Then, the mold is utilized in cooperating with the pressing process to form a pressed sheet metal, which is used as the back plate 11. The back plate 11 is the foundation determining the structural intensity of the light emitting unit 1. In more details, all of the components of the light emitting unit 1 are disposed on, screwed on or adhered to the back plate 11. Therefore, the back plate 11 is usually made of thicker sheet metal, or many additional elements are disposed to strengthen the structural intensity. As mentioned above, various molds must be prepared for manufacturing the light emitting units of different sizes and the weight of light emitting unit 1 is increased due to the thicker back plate 11.
Therefore, it is an important subject to provide a light emitting unit and a back plate thereof that have strengthened structural intensity and do not need to prepare molds of different sizes.